The next several months' activities will involve putting the new super-conducting magnet and its ancillary electronic equipment into operation. Simultaneously, further computer modeling will be done to simulate possible problems which may arise in operating the NMR spin mapping program. The pulse sequence which was found to give the best results in computer simulation will be programmed into the dedicated computer which controls the NMR pulse sequence. It is also planned that during this period NMR experiments using our old magnet system will be made on excised dog hearts in an effort to see if effects arising from ischemia can be differentiated from effects arising from hypoxia. An additional effort which has already started will be to determine the boundary of the ischemic area. The initial experiments using the super-conducting system will involve known geometrical shapes and, only after these are satisfactorily concluded, will we move onto the isolated perfused small animal heart. Here we may initially work with non-beating hearts. Beating hearts will then be mapped as described in section d and Fig. 2. The experimental emphasis will be on obtaining the limits of the ability of T1 spatial and temporal mapping to provide sensitive and specific indications of ischemic (or hypoxic) regions (induced by ligation). Biochemical analysis will be used as a correlate. An optimum display mode for the T1 mapping data will be searched for and computer and electronic means for improving resolution will be investigated. Assuming approval of our request to acquire the electronic necessary to observe 31P, NMR experiments 31P in the non-mapping mode will be undertaken.